1. Field of the Invention
The present invention relates generally to a portable terminal, and in particular, to an apparatus and a method for preventing power consumption in a portable terminal supporting access to at least two different networks.
2. Description of the Related Art
Unlicensed Mobile Access (UMA) technology refers to next generation integrated wired/wireless technology by which a Global System for Mobile Communication/General Packet Radio Service (GSM/GPRS)-based mobile communication network is connected to a wireless Local Area Network (LAN) using an unlicensed spectrum like Bluetooth® or the IEEE 802.11 standard. A UMA terminal adopting the UMA technology can freely perform voice and data communications by wire and wirelessly.
FIG. 1 is a block diagram of a conventional network supporting UMA technology.
In FIG. 1, a UMA Network (UMAN) 120 includes an Access Point (AP) 107 and a UMAN Controller (UNC) 109. The AP 107 operates as a Base Transceiver Station (BTS) 103 of a cellular network 110 to provide a radio link of a UMA terminal 101. The UNC 109 operates as a core network of a GSM/Enhanced Data Rates for Global Evolution (EDGE) Radio Access Network (GERAN) Base Station Subsystem (BSS) of the cellular network 110. Here, the BSS includes the BTS 103 and a Base Station Controller (BSC) 105. The UNC 109 includes a Security Gateway (SGW) for secure communications between the UMA terminal 101 and the UNC 109. The UMA terminal 101 is a dual-mode terminal which supports a multimedia network between a GSM and a wireless LAN. The core of a core mobile network 130 is a Mobile Switching Center (MSC). The MSC is similar to a switchboard of a Public Switched Telephone Network (PSTN) and takes charge of mobility management, position registration and/or management, authentication, Handover, Rove-In/Out, etc.
Essentially, the UMA terminal 101 is designed to support Rove-In/Out and Handover.
Rove-In/Out is technology by which a UMA terminal accesses a UMAN to use GSM voice and GPRS data services through the UMAN within a wireless LAN but accesses a cellular network to use the cellular network beyond the wireless LAN.
Handover refers to technology by which a user of a UMA terminal can continuously use a GSM voice call through a UMAN without a disconnection of the GSM voice call even when the user uses the GSM voice call within a cellular network and then goes into a wireless LAN.
Since a UMA terminal supports Rove-In/Out and Handover as described above, a user of the UMA terminal desires to use all GSM services through a UMAN within a wireless LAN. Thus, the UMA terminal, which is being provided with services through a GSM network, periodically scans an AP to check whether the UMA terminal is positioned within the wireless LAN. In other words, if the UMA terminal is positioned within the wireless LAN, the UMA terminal periodically scans the AP to use GSM services.
The method described above (i.e., the periodical scan of the AP) can contribute to improving efficiencies of Rove-In/Out and Handover. However, the frequent scan of the AP causes the portable terminal to consume large amounts of power. As a result, the lifespan of a battery used by portable terminal is reduced.
Accordingly, there is needed an apparatus and a method for preventing power consumption caused by a periodical scan of an AP to prolong the lifespan of a battery in multi-mode portable terminal.